package com.atjava.nebula.core.util.func;

import java.io.IOException;
import java.io.InputStream;
import java.net.MalformedURLException;
import java.net.URL;
import java.util.Properties;

/**
 *用来加载类，classpath下的资源文件，属性文件等。
 *getExtendResource(StringrelativePath)方法，
 *可以使用../符号来加载classpath外部的资源。
 */
public class ClassLoaderUtil {
	//private static Log log=LogFactory.getLog(ClassLoaderUtil.class);
	/**
	 *Thread.currentThread().getContextClassLoader().getResource("")
	 */

	/**
	 *加载Java类。 使用全限定类名
	 *@param className
	 *@return
	 */
	public static Class loadClass(String className) {
		try {
			return getClassLoader().loadClass(className);
		} catch (ClassNotFoundException e) {
			throw new RuntimeException("class not found '" + className + "'", e);
		}
	}

	/**
	 *得到类加载器
	 *@return
	 */
	public static ClassLoader getClassLoader() {

		return ClassLoaderUtil.class.getClassLoader();
	}

	/**
	 *提供相对于classpath的资源路径，返回文件的输入流
	 *@param relativePath 必须传递资源的相对路径。
	 *是相对于classpath的路径。
	 *如果需要查找classpath外部的资源，需要使用../来查找
	 *@return 文件输入流
	 *@throws IOException
	 *@throws MalformedURLException
	 */
	public static InputStream getStream(String relativePath)
			throws MalformedURLException, IOException {
		if (!relativePath.contains("../")) {
			return getClassLoader().getResourceAsStream(relativePath);

		} else {
			return ClassLoaderUtil.getStreamByExtendResource(relativePath);
		}

	}

	/**
	 *
	 *@param url
	 *@return
	 *@throws IOException
	 */
	public static InputStream getStream(URL url) throws IOException {
		if (url != null) {

			return url.openStream();

		} else {
			return null;
		}
	}

	/**
	 *
	 *@param relativePath 必须传递资源的相对路径。是相对于classpath的路径。
	 *如果需要查找classpath外部的资源，需要使用../来查找
	 *@return
	 *@throws MalformedURLException
	 *@throws IOException
	 */
	public static InputStream getStreamByExtendResource(String relativePath)
			throws MalformedURLException, IOException {
		return ClassLoaderUtil.getStream(ClassLoaderUtil
				.getExtendResource(relativePath));

	}

	/**
	 *提供相对于classpath的资源路径，返回属性对象，它是一个散列表
	 *@param resource
	 *@return
	 */
	public static Properties getProperties(String resource) {
		Properties properties = new Properties();
		try {
			properties.load(getStream(resource));
		} catch (IOException e) {
			throw new RuntimeException("couldn't load properties file'"
					+ resource + "'", e);
		}
		return properties;
	}

	/**
	 *得到本Class所在的ClassLoader的Classpat的绝对路径。
	 *URL形式的
	 *@return
	 */
	public static String getAbsolutePathOfClassLoaderClassPath() {

		//ClassLoaderUtil.log.info(ClassLoaderUtil.getClassLoader().getResource("").toString());
		return ClassLoaderUtil.getClassLoader().getResource("").toString();

	}

	/**
	 *
	 *@param relativePath 必须传递资源的相对路径。是相对于classpath的路径。
	 *如果需要查找classpath外部的资源，需要使用../来查找
	 *@return 资源的绝对URL
	 *@throws MalformedURLException
	 */
	public static URL getExtendResource(String relativePath)
			throws MalformedURLException {

		//ClassLoaderUtil.log.info("传入的相对路径："+relativePath) ;
		//ClassLoaderUtil.log.info(Integer.valueOf(relativePath.indexOf("../"))) ;
		if (!relativePath.contains("../")) {
			return ClassLoaderUtil.getResource(relativePath);

		}
		String classPathAbsolutePath = ClassLoaderUtil
				.getAbsolutePathOfClassLoaderClassPath();
		if (relativePath.substring(0, 1).equals("/")) {
			relativePath = relativePath.substring(1);
		}
		//ClassLoaderUtil.log.info(Integer.valueOf(relativePath.lastIndexOf("../"))) ;

		String wildcardString = relativePath.substring(0, relativePath
				.lastIndexOf("../") + 3);
		relativePath = relativePath
				.substring(relativePath.lastIndexOf("../") + 3);
		int containSum = ClassLoaderUtil.containSum(wildcardString, "../");
		classPathAbsolutePath = ClassLoaderUtil.cutLastString(
				classPathAbsolutePath, "/", containSum);
		String resourceAbsolutePath = classPathAbsolutePath + relativePath;
		//ClassLoaderUtil.log.info("绝对路径："+resourceAbsolutePath) ;
		URL resourceAbsoluteURL = new URL(resourceAbsolutePath);
		return resourceAbsoluteURL;
	}

	/**
	 *
	 *@param source
	 *@param dest
	 *@return
	 */
	private static int containSum(String source, String dest) {
		int containSum = 0;
		int destLength = dest.length();
		while (source.contains(dest)) {
			containSum = containSum + 1;
			source = source.substring(destLength);

		}

		return containSum;
	}

	/**
	 *
	 *@param source
	 *@param dest
	 *@param num
	 *@return
	 */
	private static String cutLastString(String source, String dest, int num) {
		// String cutSource=null;
		for (int i = 0; i < num; i++) {
			source = source.substring(0, source.lastIndexOf(dest, source
					.length() - 2) + 1);

		}

		return source;
	}

	/**
	 *
	 *@param resource
	 *@return
	 */
	public static URL getResource(String resource) {
		//ClassLoaderUtil.log.info("传入的相对于classpath的路径：" + resource);
		return ClassLoaderUtil.getClassLoader().getResource(resource);
	}


}
